In modern medicine, cellular therapies, regenerative medicine and tissue engineering all involve technologies for harvesting, expanding, modifying and re-implanting live viable cells and tissues. A primary example is the transplantation of isolated pancreatic islets of Langerhans for the treatment of Type I (insulin dependent) diabetes. The process of harvesting the donor cells requires the controlled separation of the desired therapeutic cells from other unwanted cells in the donor tissue.
Historically, islet isolation methods have relied upon crude cutting of the tissue into fragments, which fails to separate the target cells from the unwanted cells. Today, the field of islet transplantation relies upon enzymatic digestion processes that destroy the extracellular matrix of the tissue, releasing the entrapped islets for further processing and purification. This widely practiced procedure has drawbacks due principally to the difficulty of controlling the digestive process to yield an optimum quantity of viable cells. Moreover, the process is harsh and even toxic, causing some inevitable loss of valuable cells. Furthermore, the process relies upon the purest forms of the enzymes, which are very expensive and still subject to batch variations that have led to variability and inconsistency in attempts to optimize and standardize these processes.